The neural circuits underlying taste perception and feeding are critical for an animal's health and survival. Indeed, taste sensory information serves as the final checkpoint in determining a material's suitability for ingestion - sweet and savory substances are good sources of nutrition, while bitter compounds are often toxic. Moreover, the proper modulation of taste and feeding circuits is critical to maintaining a healthy homeostatic condition. Improper regulation can result in anorexia or obesity, both of which have dramatic health costs to an organism, with the latter being a particularly widespread problem to humans. At this time, little is known about the neural circuits that underlie taste perception and control feeding in any organism. Experiments in this proposal will examine the neural substrates of taste perception and feeding behavior in the fruit fly Drosophila melanogaster. Flies offer an excellent model system for studying this problem because they exhibit robust behavioral responses to well-defined chemical cues and have a complex nervous system that is readily amenable to a wide array of genetic manipulations that allow one to silence, activate, or monitor the activity of specific neurons. The goal of this project is to characterize the structure and function of the neural circuit underlying a simple taste behavior in Drosophila. The first aim is to determine the dendritic and axonal targets of second-order taste neurons. This will provide the anatomical framework for functional dissection of these cells. The second aim is to measure the activity of second-order neurons during taste detection. This will give insight into how the perception of different tastes is coded in the fly brain. The third aim is to investigate the function of second-order taste neurons in mediating taste behavior. The fourth aim is to uncover additional higher-order taste circuit neurons, working towards the ultimate goal of understanding a complete circuit for feeding behavior. These studies will provide important new insights into how taste information is encoded in neural circuits, and how the activity those circuits control behavior. The candidate, Dr. Michael Gordon, is a Damon Runyon Fellow in the lab of Dr. Kristin Scott at University of California, Berkeley. Having received his PhD in developmental biology at Stanford University, Dr. Gordon transitioned into studying the neural basis of behavior almost three years ago. To further this transition, he will be trained in patch-clamp electrophysiology and two-photon microscopy during the mentored portion of his award period. These techniques will be necessary for completing the proposed studies, and will enhance his future research potential. Dr. Gordon plans to start an independent research lab studying sensory perception and the control of animal behavior. PUBLIC HEALTH RELEVANCE: The goal of this project is to characterize the neural substrates of taste perception and behavior in Drosophila melanogaster. Understanding feeding regulation in this model system has the potential to shed light onto the function of similar circuits in humans that ultimately control food intake and impact body weight. Furthermore, insect feeding drastically impacts human health through the destruction of crops and spread of disease. A better understanding of these behaviors will lead to new strategies for pest control.